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PHYS(2) System Calls Manual PHYS(2) NAME phys - allow a process to access physical addresses SYNOPSIS phys(segreg, size, physadr) DESCRIPTION The argument segreg specifies a process virtual (data-space) address range of 8K bytes starting at virtual address segregx8K bytes. This address range is mapped into physical address physadrx64 bytes. Only the first sizex64 bytes of this mapping is addressable. If size is zero, any previous mapping of this virtual address range is nullified. For example, the call phys(6, 1, 0177775); will map virtual addresses 0160000-0160077 into physical addresses 017777500-017777577. In particular, virtual address 0160060 is the PDP-11 console located at physical address 017777560. This call may only be executed by the super-user. SEE ALSO PDP-11 segmentation hardware DIAGNOSTICS The function value zero is returned if the physical mapping is in ef- fect. The value -1 is returned if not super-user, if segreg is not in the range 0-7, if size is not in the range 0-127, or if the specified segreg is already used for other than a previous call to phys. BUGS This system call is obviously very machine dependent and very danger- ous. This system call is not considered a permanent part of the sys- tem. ASSEMBLER (phys = 52.) sys phys; segreg; size; physadr PDP11 PHYS(2)